I have attached (I hope) a paper one of my students and I wrote a long time ago on the hardness of porous silicon films vs. porosity etc. The references is Duttagupta,…, and Fauchet, Solid State Commun. vol 101, pp 33-37 (1997). This might be relevant to today’s discussion. Duttagupta1997
Hi all, After nearly a month of troubleshooting the fabrication of Whitesides Chamber we finally have the capability to generate a steady and linear gradient of molecules. In the presented case, we have generated a gradient of rhodamine 6G (R6G), which is a fluorophore that allows us to visualize and confirm the existence of the…
I was motivated to scan our membrane edges after looking at this image from the paper Maryna presented last week: I found a couple of pnc-Si samples with membranes still attached to the edges. I also found one sample with a membrane split almost down the middle. I coated the samples with 3nm of Au…
In this post I show the sieving coefficients of simulations with a thin membrane, a thick membrane, or a no membrane case as they approach equilibrium. The simulations were carried out for 48 hours, and plotted for 1 hour time points. Both thin and thick membrane had the same pore distribution – monodisperse 10 nm…
Initial studies into the mechanical properties of pnc-Si were carried out using the “bulge test”. With JP’s help, we’ve collected a large amount of pressure-displacement measurements. This technique has been used to investigate thin film membranes suspended over windows of different geometries e.g. Vlassak. In this study, we measure the deflection of a pressurized membrane…
Here is the most up to date figure that I’ve made to compare the simulated and experimental separation results. I went back through the x-ray crystals and remeasured the longest distances in the molecules. I used the radii to rerun the simulations and plotted them against protein and rhodamine diffusion data. Here are the results:…
In this post I will explain how I tried to use the 1D diffusion model to check the results we had in the Nature paper. Unfortunately I didn’t get the same results in the simulation and I present some ideas for the discrepancy. In the Nature paper we made simple small volume diffusion chambers and…
In this post I will show that the analytical 1D model of diffusion is similar to our 3D COMSOL model, with the exception that the times do not seem to line up. This is reasonable though since the 1D model does not take into account the non-membrane silicon pieces and enlarged volumes that occur in…
Presentation jc_9_15_2009_maryna. Paper nano9_30_305304
A temperature series was performed last week over seven wafers annealed inside the susceptor (15 nm silicon). The objective was to determine if the current configuration of target materials would show pore tunability over the temperatures of interest (900 – 1100 C). Below is a series of TEM micrographs and their corresponding histograms. At the…